On 06/06/2010 16:36, Plum wrote:
Last year my cherry tree (Cambridge) started off with a big number of
cherries which suddenly all fell off before maturing. All other prunus
types had huge harvests. A friend tells me that his cherry tree
(Surbiton) has now done this for three years running. Anyone know what
is happening, please?


This is called 'June Drop' and it is perfectly normal. It is the tree's
way of managing its resources. Your tree evidently is well pollinated,
which results in the tree setting more fruit than it can reasonably
bring to maturity. It therefore sheds many fruitlets early on so that
it can properly swell and ripen the remainder. If your tree didn't do
this, you would end up with a huge crop of tiny, near-useless fruits.

I'm surprised your other Prunus fruits aren't doing the same. A plum
tree, for example, can set so much fruit (even after June Drop) that its
branches break due to the excess weight. If you have a plum tree, you
should thin out some of the fruits. The remaining plums will be larger,
better fruits. The penalty for not doing it is, as I say, broken
branches, the wounds of which may let in Silver Leaf Disease. In severe
cases, SLD can kill the tree. Indeed, all prunus are prone to this
disease, so take care when pruning. Never prune in cold, wet weather.
I prune only on hot, dry days between May and July.
--
Spider
from high ground in SE London
gardening on clay